1. Field of the Invention
The present invention relates to the purification of air in a closed environment from the pollution to which said environment is exposed (“indoor pollution”) by filtration, and in particular refers to an apparatus that depurates said air biologically from the substances that pollute it.
More specifically, said apparatus comprises a water tank that is equipped with a biological community that has the task of absorbing and metabolizing said pollutant substances and means of water-air contact that guarantee the transfer of said pollutant substances present in the air into the tank itself.
In other words, the effectiveness of the apparatus is based upon the transfer of the pollutant substances from the air present in the domestic or working environment to the water contained in the tank and on the natural filtering capacity of the biological community present in the tank itself. Said biological community constitutes in effect a true biological filter.
2. Description of the Related Art
The substances that pollute a closed environment are emitted by sources both external thereto (i.e., structural sources or sources that regard the occupants) and internal thereto (insulating materials, materials of construction, coatings, glues, adhesives, paints, etc.).
The high number of sources of emission present in restricted spaces and the consequent presence of pollutant substances of various nature renders indoor pollution a form of pollution that is extremely complex and difficult to control. Alongside chemical factors, different biological factors concur to pollute the air in dwellings and similar premises. Amongst these factors, a particular role is played by acari, which can be found in the dust present in dwellings and in the derivatives of domestic animals. To these may be added bacterial agents capable of proliferating in air-conditioning systems, creating dangerous bioaerosols. In this way, the noxious action of the combination of chemical and biological factors can create adverse synergistic effects on the health of a person.
Nowadays, there is an increasingly widespread sensitivity to the problems that this type of pollution entails, above all in relation to working and/or domestic environments.
Currently, since the control of the sources of indoor pollution is problematical, both on account of their variety and on account of the difficulty of acting on consolidated situations, different solutions are envisaged.
A first known solution consists in intervening by means of ventilation, through the introduction of external air (in the case of limited and distributed sources). A second known solution envisages localized forms of extraction (in the case of extremely large and delimited sources). However, even though said solutions are capable of limiting the concentrations of pollutants below the safety thresholds, a disadvantage is represented precisely by the difficulty of their application in domestic or working environments.
Consequently, in said situations, the only possibility of intervention on the concentration of pollutants is constituted by filtration, both of the air introduced from outside and of the recirculation air. But also this solution presents the disadvantage of being difficult to provide, above all in pre-existing buildings and taking into account the objective technical and economic limitations. In addition, there is the need to take into account aspects regarding maintenance of filtering systems, which, in addition to representing a further economic burden, can be noxious for the persons occupying an environment, on account of the release of pollutant substances from saturated filters.